In the volumetric dispensing of heated fluids such as soups, it has been common practice to use vented trap valves to dispense metered quantities of the soup. The use of such vents has been essential to insure that reasonably accurate and reliable unit volumes of soup or the like are dispensed for each actuation of the trap valves. When chunky and/or high solids content soups are to be dispensed, however, the vents tend to clog, resulting in improper and unreliable operation and/or unsanitary conditions due to the difficulty of properly cleaning and sterilizing the vent passages. Prior art attempts to handle chunky or high solids content soups have resorted to relatively ungainly and cumbersome trap valve structures.
Thus, there is a long felt need in the art for soup dispensers which can be readily cleaned to maintain high sanitary requirements; which obviate the need for venting the trap valves; and which include volumetric trap valves of simplistic construction coupled with accurate and reliable operation.